Product: TP Kasa KP125M - Matter Smart Plugs
Setup: Unifi Network - Multiple VLANs including an IoT one. Main Lan can talk out and receive back but IoT lan cannot establish connection first.
Apple TVs 4k (2nd gen) on main lan
All IoT devices on IoT network

Zero problems with that setup all devices are responding fine, Bluetooth, Wi-Fi, hubs, etc

Here comes the first Matter device. My understanding was that the 2nd gen supported Matter via software update and did not need any additional items to use. 3rd gen ATV only offers thread capability that wasn’t HomeKit exclusive previously from what I’ve read. So I logged into my IoT network and added the Kasa Matter plugs and man oh man it was a pain. Multiple failed to add, and when added no response. The Kasa app still see the devices since they are on Wi-Fi and I updated their firmware but that did not solve the no response issue. As far as I can tell these are not Matter over Thread devices (unfortunate and may be returned for that reason alone) and should function just like any other Wi-Fi IoT device on the IoT network.

Anyone have any insight with these?

I will try to add one to the main lan to see if that causes it to respond. Don’t know if the Matter protocol just cannot talk over VLANs if the IoT network is restricted to initiate communication.

Anyone have insight with Matter and VLANs in general?

TL;DR: Matter plugs on IoT network not responding in home app but still usable in Kasa app. All regular HomeKit devices function fine. Anyone here have a lot of experience with Matter and VLANs?